Evaluation of Low-maintenance Landscape Roses in Central Florida

摘要

Environmental conditions in Florida are favorable for the development and persistence of insects and diseases that affect rose (Rosa sp.) plants, necessitating periodic applications of pesticides to maintain plant appearance. In addition, nutrient-deficient and well-drained soils in Florida force gardeners to provide supplemental fertilizer and water. Landscape performance is rarely considered for the development of new rose cultivars; consequently, careful selection of cultivars adapted to local conditions is necessary to reduce maintenance. The objective of this study was to develop recommendations of own-root, low-maintenance roses among 11 old garden and modern cultivars for central Florida. Plants were provided with minimal amounts of water andfertilizer, no control for diseases and insects, and no grooming or deadheading. Weekly evaluations were performed on all plants for plant quality, flower coverage; and incidence of black spot (caused by Diplocavpon rosae), cercospora leaf spot (causedby Cercospora rosicola), and foliar damage [caused by chilli thrips (Scirtothrips dorsalis)]. Damage caused by the foliar diseases and chilli thrips were the major factors that affected plant quality, vigor, and subsequently, flower production. Differences in susceptibility to these three factors were found among cultivars, enabling the classification of the 11 cultivars as recommended, cautiously recommended, and not recommended for central Florida. After two years, 'Mrs. B.R. Cant' appeared to be themost suited for central Florida as plant quality and flower production were fairly constant. 'Duchesse de Brabant', 'RADrazz' (Knock Out~R), and 'Spice' were the next best performers and are cautiously recommended for central Florida. These cultivars were minimally affected by both diseases, showing low severity of yellowing and defoliation nor a decline in flower production. "Bailey Red", 'Old Blush', 'Belinda's Dream', 'Perle d'Or', 'BUCbi' (Carefree Beauty~(TM)), 'Mutabilis', and 'WEKcisbako' (Home Run~R) had severe defoliation, poor growth, and low vigor in this study and do not appear to be low-maintenance landscape roses for central Florida.